Something wrong with symfony/http-foundation ?

Which version of core are you on?

We are on 10.3.10 and it seemed like the issue started with that. But then I just downgraded symfony/http-foundation to v6.4.13 and issue went away.

Thanks. 🐛 DefaultExceptionHtmlSubscriber should not clone the request for 401s Active is committed but not in a tagged release of 10.3 yet. Pretty sure this is the same thing.

I've created module that breaks the site https://github.com/hkirsman/symfony_http_foundation_debugging

composer require drupal/core-composer-scaffold:10.3.10 drupal/core-recommended:10.3.10 drupal/core-dev:10.3.10 drupal/core:10.3.10  -W 
install -d web/modules/custom
cd web/modules/custom
git clone https://github.com/hkirsman/symfony_http_foundation_debugging.git
drush en symfony_http_foundation_debugging -y
Go to path /%5C

I tested that on minimal install and same issue happened.

Thanks @catch! I'll try that last issue tomorrow. It does sound like it could be it.

Can confirm the memory error when visiting URL /%5C on Drupal 10.3.10 and symfony/http-foundation v6.4.16.

I tried the fix from https://www.drupal.org/project/drupal/issues/3486972 🐛 DefaultExceptionHtmlSubscriber should not clone the request for 401s Active It does get rid of out of memory issue, but then again it shows white page with plain text "Invalid URI: A URI cannot contain a backslash." It used to Drupal normal "page not found" page.

Adding another related issue here. I suspect this issue could be closed as a duplicate? If not, please re-open.

Note, some of the related issues do have merge requests that need review, so feel free to review :)